1. Technical Field
The present invention relates to optical laser fibers and methods of using them in surgical procedures. More particularly, the present invention relates to side-firing laser fibers and methods of using them in the treatment of various surgical procedures, such as benign prostatic hyperplasia.
2. Background Information
Optical lasers, such as Nd:YAG lasers, have found increasing applications in the conduct of surgical procedures. One advantage of laser surgery is that it can often be performed through a relatively small incision or by insertion into an existing body passageway. Laser surgical procedures can frequently be performed on an out-patient basis, resulting in significantly lower cost and less inconvenience to the patient. Dramatic shortening in recovery time is often seen in comparison to traditional surgery which it replaces. For these reasons, efforts continue to be directed toward the development of new laser apparatus and improved methods of surgical treatment using medical lasers.
Various configurations of optical fibers have been developed for different types of surgical procedures. Recently, side-firing fibers have been found particularly useful in a variety of situations. A typical side-firing laser optical fiber utilizes a mirror or other optical surface to reflect a laser beam traveling down a fiber so as to emerge from the tip of the fiber at a selected angle. This permits the laser beam to be directed onto tissue surrounding body passageways, or the like, without any incision being required. It also permits use of lasers in other cramped environments.
One use for which side-firing fibers is currently being tested is in connection with the treatment of benign prostatic hyperplasia, often referred to as "BPH" for purposes of brevity. BPH is a condition involving an enlarged prostate gland, typically increasing between about two and four times normal size. This condition occurs in approximately one-third of all males over age 60. Currently, approximately 400,000 cases are treated each year in the United States alone, and this number can be expected to increase as the population ages.
BPH is characterized by nocturia (bed-wetting), hesitancy in urination, decreased force of urinary stream, post-voiding dribbling, and a sensation of incomplete emptying. Although incontinence is the most common and emotionally disturbing complaint, it is possible for the enlargement to continue to the point of acute urinary retention. That problem is both painful and dangerous, requiring immediate treatment.
The most common treatment at the present time is known as transurethral resection of the prostate ("TURP"), which involves removal of portions of the prostate gland using a special cytoscope inserted into the urethra. Following a TURP procedure, a typical patient must wait about seven to fourteen days before resuming normal activities, and there is a high incidence of post-operative problems. For example, about 95% of TURP patients experience retrograde ejaculation. It has also been reported that it may take upward of 50 to 100 procedures for an physician to attain true skill at performing TURP procedures; one can only wonder at the fate of the first 50 to 100 patients of each such physician.
Although testing is still far from complete, initial reports indicate that laser treatment of BPH is an improvement over TURP procedures. One such procedure involves the use of side-firing fibers to direct Nd:YAG laser energy onto enlarged prostate tissue. This results in some surface ablation, but the primary benefit is deep tissue coagulation and subsequent tissue necrosis, which effects a reduction in the size of the prostate over a period of several months following the procedure as the necrotic tissue sloughs off. This technique is reported to be much easier to perform, resulting in proficiency after only five to ten procedures. It also has a much lower reported incidence of problems such as retrograde ejaculation--only about 25% of patients report that adverse side-effect.
Hence, it will be appreciated that BPH looms as a major problem for which side-firing laser fibers have shown promise in treating. Yet, side-firing fibers suffer from drawbacks which require improvement.
For example, even though side-firing fibers are intended to be used in a non-contact mode so that laser energy will penetrate into the tissue rather than simply ablate surface tissue, it is not uncommon for the fiber to inadvertently come into contact with the tissue during a laser surgical procedure. It is well known that unprotected quartz fibers become burnt and broken when they come into contact with tissue. To overcome this problem, it has become common to protect quartz fibers with a metal cap which will not break or burn when it inadvertently comes into contact with a patient's tissue. The use of a metal cap causes other problems, however. For example, leakage of laser energy causes metal tips to become heated. When inadvertently touched to tissue, it is common for such heated tips to stick to and thereby cause unwanted damage to tissue. The damage is exacerbated when the tip is forcibly removed from the tissue to which it has become stuck. Although it is usual to irrigate metal tipped fibers in order to try and lower the temperature of the metal tips, such irrigation is frequently only partly successful. Hence, even when using irrigation, some damage occurs due to inadvertent touching of the tip to tissue.
Further, it occasionally happens that a laser is fired accidentally while the tip is outside the patient or when the irrigation is not in operation. When this happens with a side-firing tip using a metal cap, the tip is usually damaged and becomes unusable.
From the foregoing, it will be appreciated that it would be a significant improvement if new side-firing laser fibers were to be developed which would avoid the problems of unprotected quartz tips, yet would also avoid the problems encountered when one uses a metal cap to protect the tip of a quartz fiber. It would also be an important advance if improved methods were to be developed for treatment of BPH or other maladies treatable by side-firing laser fibers.